Field of the Invention and Related Art Statement
The invention relates to a projection exposure device and position alignment device and position alignment method.
The photolithography method has been applied widely in various fields, wherein a prescribed pattern is photographically imprinted by an exposure device on the surface of a printed circuit substrate coated with photosensitive materials such as the photo resist, thereafter the pattern is formed on the substrate by etching process. Printed circuit boards have also been fabricated by using an exposure device in recent years.
The projection exposure device is a type of depicting a circuit pattern of a photo mask on a printed circuit substrate in the same size as the mask or in certain magnification by projecting and exposing the pattern through an optical system such as the projection exposure lens or the like. It has been conventionally applied in the fabrication of integrated circuits, and in recent years, this projection exposure device has been tried in the fabrication of printed circuit boards.
When exposing by the exposure device, the photo mask and the circuit board must be aligned, usually by positioning alignment marks on both the photo mask side and the board side, respectively, thereafter projecting the alignment mark of the photo mask onto the board and aligning it with the alignment mark of the board by observing through a microscope. When projecting the mark of the photo mask side, rays outside the range of the exposure wavelength is commonly used because the photo resist is sensitive to the rays of exposure wavelength. Ultra-violet rays are usually used as exposure wavelength while infrared rays for projecting the mark.
However, as the projection exposure device projects the mark of a photo mask through an optical system such as the projection exposure lens in line with the exposure wavelength, if rays of wavelengths other than the exposure wavelength is used for the mark projection, precise positional alignment may not be realized due to the positional shift of the formed mark image. To resolve such problem requires correcting lenses and a device for controlling the position of the correcting lenses, which will further increase the cost of the device.
The object of the invention is to resolve such problems of the conventional technology described above.